[PATCH v4 01/21] KVM: arm64: Add hyp_spin_is_locked() for basic locking assertions at EL2
From: Quentin Perret <hidden>
Date: 2021-08-09 15:24:58
Also in:
kvmarm, lkml
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
From: Will Deacon <will@kernel.org> Introduce hyp_spin_is_locked() so that functions can easily assert that a given lock is held (albeit possibly by another CPU!) without having to drag full lockdep support up to EL2. Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Quentin Perret <redacted> --- arch/arm64/kvm/hyp/include/nvhe/spinlock.h | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/arch/arm64/kvm/hyp/include/nvhe/spinlock.h b/arch/arm64/kvm/hyp/include/nvhe/spinlock.h
index 76b537f8d1c6..04f65b655fcf 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/spinlock.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/spinlock.h@@ -15,6 +15,7 @@ #include <asm/alternative.h> #include <asm/lse.h> +#include <asm/rwonce.h> typedef union hyp_spinlock { u32 __val;
@@ -89,4 +90,11 @@ static inline void hyp_spin_unlock(hyp_spinlock_t *lock) : "memory"); } +static inline bool hyp_spin_is_locked(hyp_spinlock_t *lock) +{ + hyp_spinlock_t lockval = READ_ONCE(*lock); + + return lockval.owner != lockval.next; +} + #endif /* __ARM64_KVM_NVHE_SPINLOCK_H__ */
--
2.32.0.605.g8dce9f2422-goog
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